Imaging apparatus

ABSTRACT

An image carrying cylinder portion and optical system for use in the support of an image. The cylinder portion is transparent and light image is flowingly projected along a fixed path through the diameter of the cylinder from the inside to the outside surface. The cylinder portion is rotated through the light path along which the light image is projected in sychronism, flowing with the moving cylinder portion so that both the cylinder portion and the light image move through an image plane of the light image projection system.

United States Patent 1 Zurovskis et al.

[ 51 Feb. 27, 1973 1 IMAGING APPARATUS [75] Inventors: Egon Zurovskis, Penfield; Raymond K. Egnaczak, Williamson, both of N.Y.

[73] Assignee: Xerox Corporation, Rochester, NY,

[22] Filed: Dec. 9, 1971 [211 App]. No.2 206,476

I Related U.S. Application Data [63] Continuation of Ser. No. 876,921, Nov. 14, 1969.

[52] U.S. C1 ..355/8, 355/47 [51] Int. Cl. ..G03g 15/04 [58]- Field of Search ..355/8, 47, 48; 204/110, 181,

[56] References Cited UNITED STATES PATENTS 3 1924 Cook ..240/49 2,288,177 6/1942 Bailey ..240/49 3,062,094 11/1962 Mayo ..355/47 X 3,427,242 2/1969 Mihajlou ..204/1 81 X Primary ExaminerJohn M. Horan Assistant Examiner-E. M. Bero Attorney-James J. Ralabatc et al.

[57] ABSTRACT An image carrying cylinder portion and optical system for use in the support of an image. The cylinder portion is transparent and light image is flowingly projected along a fixed path through the diameter of the cylinder from the inside to the outside surface. The cylinder portion is rotated through the light path along which the light image is projected in sychronism, flowing with the moving cylinder portion so that both the cylinder portion and the light image move through an image plane of the light image projection system.

5 Claims, 10 Drawing Figures PATENTEDFEBZYW 3,718,393]

SHEET 10F 7 INVENTORS EGON ZUROVSKIS BY RAYMOND K. EGNACZAK PATENTEDFEBZYW 3,718,393

SHEET 2 OF 7 FIG. 2

P I NT nrmUmn j 3,718,393 I sum nor 1 PATENI FE827I975 SHEET 70F 7 IMAGING APPARATUS This is a continuation of application Ser. No. 876,921, filed Nov. 14,1969.

This invention relates to imaging systems and more specifically to improved image forming members.

Recently, a new invention was discovered for forming black and white or full color images through the use of photoelectrophoresis. The invention, in its basic form, is described in US. Pat. Nos. 3,384,488; 3,384,565; 3,384,566 and 3,383,993 all issued on May 21, I968. The system disclosed therein utilizes photoelectrophoretic particles which migrate in image configuration providing a visual image at one or both of two electrodes between which the particles are placed in the suspension. The particles are photosensitive and apparently undergo a net change in charge polarity or a polarity alteration by interaction with one of the electrodes upon exposure to activating electromagnetic radiation. No other photosensitive elements or material are required; hence, this provides a very simple and inexpensive imaging technique. Mixtures of two or more differently colored particles can secure various colors of images. Particles in these mixes may have overlapping or separate spectral response curves and are usable in subtractive color synthesis. The particles will migrate from one of the electrodes under the influence of an electric field when struck with energy of a wavelength within the spectral response of the colored particles. I

Apparatus has been invented to better utilize the above process in an automated system shown in U.S. Pat. No. 3,427,242 issued Feb. I1, 1969 which described a continuous apparatus embodiment of the above process. The commercial significance of a continuous imaging machine utilizing the above referred to process is an important consideration in developing new and improved embodiments. For example, although excellent images can be formed with the continuous apparatus it is necessary to position the optical system through a glass or transparent drum or to use mirrors inside a drum to bend the optical path around it. The invention herein is an improved system for overcoming difficulties in utilizing the aforementioned photoelectrophoretic process in an automated mode. Therefore, it is an object of this invention to improve automated photoelectrophoretic process machines. Another object of this invention is to improve components for use in automated photoelectrophoretic machines.

Still another object of this invention is to improve utilization'of optical equipment in conjunction with automated machinery. Another object of this invention is to improve rotary configuration of photoelectrophoretic machines;

Yet a further object of this invention is to utilize an optical path unobstructed by non-imaging refractive members. A further object is to improve rotary imaging systems using transparent members by placing all optical components external to the members.

These and other objects of this invention are accomplished by providing a drum sector member for forming and maintaining an image formed of particles migrated to it during exposure to electromagnetic radiation through the member at a fixed position whereat the member is contacted by an electrode for forming the image and the image is projected in synchronous flowing movement with the member but through the diameter of the member.

The invention herein is described and illustrated in a specific embodiment having specific components listed for carrying" out the functions of the apparatus. Nevertheless, the invention need not be thought of as being confined to such a specific showing and should be construed broadly within the scope of the claims. Any and all equivalent structures known to those skilled in the art can be substituted for specific apparatus disclosed as long as the substituted apparatus achieves a similar function. It may be that other processes or apparatus will be invented having similar needs to those fulfilled by the apparatus described and claimed herein and it is the intention herein to describe an invention for use in apparatus other than the embodiment shown.

The above and other objects and advantages will become apparent to those skilled in the art after reading the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 schematically illustrates a preferred embodiment of a machine for forming photoelectrophoretic images; v

FIG. 2 is a front view partially sectioned of the image carrying member housing as seen from the cleaning station of FIG. 1;

FIG. 3 is another view of the image carrying housing from the cleaning module with the image member in imaging orientation;

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 3;

FIG. 5 is a side view of the image carrying member mechanism as viewed from the orientation of FIG. 1;

FIG. 6 is a side view of the optical scanning system and drive;

FIG. 7 is a view taken along line 7-7 of FIG. 6;

FIG. 8 is a rear view of the optical driving system;

FIG. 9 is a sectional view of the torque tube drive of the driving mechanism of FIG. 8, and

FIG. 10 is an exploded perspective schematic illustration of the drive mechanism.

OPERATION OF BASIC SYSTEM A detailed description of the operation and theories relating to the actual imaging system automated by this invention and discussing the interaction of the photoelectrophoretic particles in the suspension used for image formation is found in the above cited patents. The imaging system therein described and which can be employed in the apparatus described herein operates by producing electromagnetic radiation in image configuration to which the individual photoelectrophoretic particles within the suspension are sensitive. The activating radiation and an electric field across the imaging suspension combine between two electrodes in the imaging area. An electrode referred to as the transparent injecting electrode is maintained electrically positive relative to imaging electrodes interfacing with it at the imaging area across the photosensitive suspension. Therefore, particles within the suspension that are negatively charged will be attracted to the relatively positive, transparent injecting electrode.

The injecting electrode" is so named because it is thought to inject electrical charges into activated photosensitive particles during imaging. The term photosensitive" for the purposes of this invention refers to the property of a particle which, once attracted to the injecting electrode, will alter its polarity and migrate away from the electrode under the influence of an applied electric field when exposed to activating electromagnetic radiation. The term suspension may be defined as a system having solid particles dispersed in a solid, liquid or gas. Nevertheless, the suspension used in the embodiment of this invention described herein is of the general type having a solid suspended in a liquid carrier. The term imaging electrode is used to describe that electrode which interfaces with the injecting electrode through the suspension and which once contacted by activated photosensitive particles will not inject sufficient charge into them to cause them to migrate from the imaging electrode surface. The imaging zone or imaging area is that zone between two electrodes where photoelectrophoretic imaging occurs.

The particles within the suspension are generally insulating when not struck by activatingradiation within their spectral response curve. The negative particles come into contact with or are closely adjacent to the injecting electrode and remain in that position under the influence of the applied electric field until they are exposed to activating electromagnetic radiation. The particles near the surface of the injecting electrode make up the potential imaging particles for the final image to be reproduced thereon. When activating radiation strikes the particles, it makes them conductive creating an electrical junction of charge carriers which may be considered mobile in nature. The negative charge carriers of the electrical junction orient themselves toward the positive injecting electrode while the positive charge carriers move toward the imaging electrode. The negative charge carriers near the particle-electrode interface at the injecting electrode can move across the short distance between the particle and the surface of the electrode leaving the particle with a net positive charge. These polarity altered, net positively charged particles are now repelled away from the positive surface of the injecting electrode and are attracted to the negative surface of the imaging electrode. Accordingly, the particles struck by activating radiation of a wavelength with which they are sensitive, i.e., a wavelength which will cause the formation of an electrical junction within the particles, move away from the injecting electrode to the imaging electrode leaving behind only particles which are not .exposed to sufficient electromagnetic radiation in their responsive range to undergo this change.

Consequently, if all the particles in the system are sensitive to one wavelength of light or another and the system is exposed to an image with that wavelength of light, a positive image will be formed on the surface of the injecting electrode by the subtraction of bound particles from its surface leaving behind particles in the unexposed areas only. The polarities on the system can be reversed and imaging will occur. The system may be operated with dispersions of particles which initially take on a net positive charge or a net negative charge.

The imaging suspension may contain one, two, three or more different particles of various colors having various ranges of spectral response. in a monochromatic system the particles included in the suspension may be of any color and produce any color area the particle spectral response is relatively immaterial as long as there is a response in some region of the spectrum which can be matched by a convenient radiation exposure source. In polychromatic systems the particles may be selected so that particles of different colors respond to different wavelengths For photoelectrophoretic imaging to occur, these steps (not necessarily listed in the sequence that they occur) take place: (1) migration of the particles toward the injecting electrode due to the influence of the field, (2) the generation of charge carriers within the particles when struck with activating radiation, (3) particle deposition on or near the injecting electrode surface, (4) phenomena associated with the forming of an electrical junction between the particles and the injecting electrode, (5) particle charge exchange with the injecting electrode, (6) electrophoretic migration toward the imaging electrode, and (7) particle deposition on the imaging electrode. This leaves a positive image on the injecting electrode.

After the image is formed on the injecting electrode, the electrode may be brought into interface with a transfer member which has a charge polarity opposite to that of the imaging electrode. The injecting electrode is now maintained negative relative to the transfer member. The particles having a net negative charge will be attracted to the relatively positive transfer member. I a if material is interposed between the transfer member and the particle image, the particles will be attracted to the support material. Therefore, a photographically positive image can be formed on any support material.

THE MACHINE COMPONENTS Referring now to FIG. 1, a preferred embodiment for an automated machine to produce images according to the aforementioned process is shown. An injecting electrode 1 forms a portion of a transparent cylinder member held in a housing 2 and is journaled for rotation in the direction indicated by the arrow about a shaft 3. The injecting electrode 1 is made up of a layer of optically transparent glass 4 overcoated with a thin optically transparent layer 5 of tin oxide or other electrically conducting material. A particular material suitable for this electrode is available under the name of NESA glass manufactured by Pittsburgh Plate Glass Company, Pittsburgh, Pa. The injecting electrode. 1 is formed as a portion of a cylinder housed within the metal housing frame 2.

The machine shown schematically in FIG. 1 is positioned where the injecting electrode cylinder portion is about to be rotated in a predetermined path to a cleaning station labeled A whereat a plurality of cleaning members such as belts 6, 7 and 8 contact the conductive surface 5 of the injecting electrode. On the opposite side of the injecting electrode held stationary within the machine frame are lamps 9, l0 and 11 juxtaposed to the belts 6, 7 and 8 respectively. When activated, the lamps send flood light illumination through the transparent injecting electrode at the contact areas between the electrode and the cleaning belts. Each of the belts are activated by one of the cylinders 12, 13 and 14 to contact the injecting electrode 1. These cylinders operate to press the belts against the conductive surface of the injecting electrode in order to clean The next station in the path of movement of the injecting electrode is the imaging station B. Here, on the first pass of the injecting electrode 1 through station B the first imaging member, the imaging electrode 16 interfaces with the conductive surface 5 of the injecting electrode 1.

The optical system at station C projects an image to the imaging'zone between the electrodes 1 and 16 at station B. The optical system has a lamp carriage l7 journaled at an axis 18 to oscillate in a path concentric with the platen 19. A document 20 is positioned at the platen 19. The lamps are shown at the start of scan position and as the injecting electrode 1 passes through the imaging area at station B the lamps move across the platen 19 projecting an image at station B through suitable mirrors 21-23, a lens 24 and the transparent electrode 1.

The imaging electrode roller 16 moves in rolling interface relation with the conductive surface 5 of the injecting electrode 1 and functions both to supply suspension to the injecting electrode and to image that suspension between the injecting electrode surface 5 and the surface of the electrode 16. The injecting electrode continues to rotate at a constant velocity through a complete rotation of the predetermined path. It travels without interacting with any elements located around the periphery of the path until it again reaches station B at the imaging zone. Now, however, the imaging electrode 16 has been moved out of its interfacing position by operation of a cylinder 25 which lowers the electrode 16 and the housing 26 supporting it. Further, a cylinder 27 moves a carriage 28 along a horizontal path carrying with it the housing 26 which supports the imaging electrode 16. Also moved in the carriage 28 is a second imaging member, the imaging electrode 29 within a housing 30 maintaining it. A cylinder 31 operates through an eccentric 32 to raise the housing 30 and the second imaging electrode 29 at the imaging zone at the imaging station B of the machine. The second imaging electrode 29 moves in rolling interface with the injecting electrode surface 5 as that surface passes through the imaging station B. At this time the original 20 on the platen 19 is again illuminated by the scanning lamps 33 at the optical system station C. The scan is synchronized with the movement of the injecting electrode to project a flowing image in registration with the first projection and moving at the same rate as is the surface 5 at the imaging zone.

The injecting electrode 1 then passes into the transfer station D. At station D is a transfer roller 40. A sheet of support material held in the supply tray 41 is lifted therefrom and is carried through a vacuum transport 42 to the transfer roller 40. It is gripped by a gripper mechanism 43 on the transfer roller40 and rotated to the injecting electrode 1 passing at station D. Before the sheet 44 contacts the surface 5 of the injecting electrode 1 it is moistened with a liquid that will aid in transferring the particles of the suspension on the surface 5. The wetting is accomplished by a wetting bar 45 rotated in a pool of suitable wetting material held within a tank 46. The transfer member rotates the support material 44 in rolling contact with the surface 5 of the injecting electrode 1 under the influence of a suitable electric field causing the particles forming the image on the injecting electrode to be transferred to the support material. The support material is removed from the transfer member by picker fingers 47 and a release mechanism on the grippers. Next it is carried on a vacuum transport 48 to suitable receptacle.

INJECTING ELECTRODE HOUSING The lamps 9, 10 and 11 shown in the figures are used in conjunction with the cleaning module belts 6, 7 and 8 respectively to provide flood lighting for activating the particles remaining on the injecting electrode causing them to migrate toward the cleaning belts under the influence of an applied electric field. The lamps are mounted into bracket mounts 140 and 141 through sockets 142. The lamps can be fluorescent lamps or any lamps emitting broad spectral radiation to activate the photoelectrophoretic particles that may remain on the injecting electrode after transfer. The brackets 140 and 141 are fastened to wedge shape spacers 143 and 144. These in turn mount on a black light shield 145.

The light shield has an aperture slot 146 at the imaging station of the machine. The aperture 146 is a field stop near the image plane of the optical system to limit the image area illuminated at the imaging electrode. At the opposite endof the light shield is an aperture 147 through which the light rays from the optical system pass to reach the image plane. The light shield is used to prevent ambient light from reaching the imaging station and interfering with the illumination used for forming the image. The light shield, light mounting brackets and those members associated therewith are stationary within the-machine and once positioned according to the optical'path requirements do not move during the operation of the machine. Rotating around the light shield and the apparatus appended thereto is the injecting electrode and its associated housing.

The injecting electrode is held in an electrode support comprised of a glass holder 148 and a glass support member 149 which, along with the coated transparent glass electrode, form a sandwich for mounting on the cylindrical electrode housing referred to as the drum frame 150. Mounted on the drum frame 150 is a grooved-overframe 151 having a groove 152 across the length thereof. This groove functions cooperatively with the nozzles 131 of the cleaning module in order to remove excess cleaning fluid and suspension that rides along the glass and glass support and overframe during the rotation of the injecting electrode housing through the cleaning station.

The drum frame is rotated about fixed shafts 153 and 154 which fasten to the light shield 145 through the wedge shaped spacers 143 and 144. The ends of the drum frame are closed by two end caps 155 and 156 which are each mounted on a bearing housing, 157 and 158 respectively, on each side of the assembly. The bearing housing 157 is mounted through a bearing 159 to the machine drum support frame 160.

Located in the end cap 155 and the bearing housing 157 are a series of apertures 161 that are drilled through the entire housing and end cap and into the cavity of the drum frame 150. The purpose of these holes is to provide for air flow forced from a fan (not shown) to remove any vapors out of the drum cavity that might otherwise accumulate due to the materials used in the process. The bearing housing and end cap are mounted to the fixed frame 153 by bearings 162 and 163 to permit rotation of the drum frame and injecting electrode around the fixed shaft 153. The fixed shaft 153 has a flat 164 at the end thereof for location within the main drum support 160 to set the aperture 146 in the proper position for imaging at the imaging electrode station B.

On the other side of the drum frame is the fixed shaft 154. This shaft is in fact a hollow tube with a hollow inner portion 166 enabling air flow therethrough. An air fitting 165, attached to the outboard end of the fixed shaft, couples to an air supply. The hollow 166 connects with an annular groove 167 which in turn connects to a slot 168 in the bearing housing 158. rings 169 and 170 effectively seal the passage from air leaks during operation of the system. The slot 168 feeds into a piston housing 171 having a backing member 172, an air chamber 173, a piston valve seal 174, piston valve 175 and return spring 176. Also cut into the piston housing 171 is a chamber 177 which connects to a clean-out slot 178 in the glass support member 149.

A register pin 179 is located within the bearing housing 158. The bearing housing rotates about the fixed shaft 154 through two bearings 180 and 181. The bearing housing 158 is formed from a long hollow tube with a tapered surface 182 near the pin 179. At the long shaft end of the bearing housing 158 near the bearing 180 is a lock nut 183 which couples the housing with the gear box 184. The gear box 184 contains a'worm gear 185 which is key locked to the sprocket 186 delivering power from the main drive motor. The worm causes a hollow shaft 187 to rotate. The shaft 187 has a slot 188 therein for intermeshing with the register pin 179. The lock nut draws the shaft 187 into tight contact with the taper 182 of the bearing housing 158. The slotted portion of the hollow shaft 187 is tapered to match the taper of bearing housing 158 to ensure that the slot 188 covers the register pin 179 for positive driving of the injecting electrode drum assembly.

I The driving is accomplished by rotation through a sprocket 186 and hollow drive shaft 187 through cooperation with the register pin 179 thus turning the drum assembly with the injecting electrode glass therein. However, the movement does not affect the stationary positioning of the cleaning flood lamps 9, and 11 or the light shield 145. These remain fixed and stationary as positioned by the flat 164 of the fixed shaft 153. The worm gear 185 turns the sprocket 186 which is keyed to the hollow shaft 187 by a key 192. The shaft 187 is separated from the gear box housing 184 by two roller bearings 193 and 194. The housing is sealed to prevent oil leakage around the hollow shaft 187 by a drum side seal 195 and a frame side seal 196.

Excess suspension is cleaned from the surface of the drum frame through the fixed shaft 154 and piston housing 171. This cleanout function is actuated by predetermined times during the cycle by activating a valve actuator trigger 189.

On the gear box 184 is the valve actuator trigger 189 having an air fitting 190 to force air behind a piston 191 which is programmed to trigger the piston rod to strike the piston valve causing a burst of air to flow through the cleanout slot 178. This sequence occurs when the cleanout slot 178 is sealed by contact with either of the imaging electrodes 16 or 29. By this operation, all of the materials in the slot are air blasted completely through and out the other end thereof.

OPTICAL SCANNING SYSTEM The optical projection system which transmits light radiation from an object to the imaging position at the imaging area maintains the object on the plate 19 the upper surface of which is at the object plane of the lens 24 maintained in the lens barrel 300. A platen cover 301 maintains the document in contact with the platen 19 and prevents external light from penetrating through the machine environment. A handle 302 is at tached to the platen cover 301 for opening the cover during placement of the object on the platen.

The lamps 33 are held in a light reflector 303 by lamp holders 304 and 305. The lamp holders are made of a high heat resistant ceramic material necessary because of the heat output of the lamps used. The reflectors 303 are formed of hollow polished metal tubing capable of circulating cool air, water or other fluids therethrough to control the temperature of the lamps 33. The lamps are shown in FIG. 14 in the standby position and when so positioned, they are located between an upper heat sink 306 having chambers 307 located therein and a lower heat sink 308 with chambers 309 therein. The chambers are for the circulation of cool fluid to remove heat from the area of the lamps.

For this reason an air or liquid fitting 310 is attached to the lower heat sink to permit the flow of fluids through the chambers 309. Similar fittings and fluid flow through the chambers 307 of the upper heat sink 306 are incorporated into the machine but not shown. The lower heat sink 308 is maintained on a frame 311 which is fastened to the main optical frame of the machine on a flange 312 provided for this purpose.

During projection of the object to the image zone, the lamps are rotated about an axis coincident with the mirror shaft 313 by the action of the lamp frames including a metal side frame 314 and a truss frame'17. The truss supports the main weight'of the lamps while the side frame 314 ensures uniform movement of both sides of the lamp housing 315. The mirror shaft 313 causes the oscillation of the mirror 21 about the same axis. The lower optical frame 316 supports upper optical frame 317 and the platen assembly. The lower optical frame 316 is removable from the machine for maintenance by rotating it about a rod 318. When in position for projection, it is optically set on the upper frame by a setup ball 319. the alignment positions the lower optical frame 136 relative to the center of the injecting electrode carriage housing through the use of shims 320 in the upper optical frame 317.

The scanning lamps produce light for reflection from the object. The optical path extends through the oscillating mirror 21, a shutter and optical filter box 321, the lens 24 held within the lens barrel 300 to two mirrors 22 and 23 and the inside portion of the injecting electrode 1 through the large opening in the drum frame 150. The dashed line 322 indicates the optical path. The fixed mirrors 22 and 23 are adjustable to be pivoted about a rod 323 within the frame 324 mounting the two mirrors by an adjusting screw 325 and an adjusting nut 326 revolving cooperatively on the screw thread. The nut, of course, can be locked onto the screw once the adjustment has been made and the optical path falls precisely as desired between the lens and the aperture 146 in the aperture box 145.

Along the optical path is the shutter and filter box 321 which operates an automated shutter kept in an open position during the entire scan of the lamps and scanning mirror and then closed on the return stroke of the scan. This eliminates any light from penetrating the system when the lamps are, returned to their standby position since the lamps are maintained lit during the return stroke. The filters within the box contain optical filtering means such as neutral density filters or the like in order to make optical corrections between the object and the imaging suspension.

As the injecting electrode drum rotates the main. optical cam 327 housed on the shaft 187 drives the scanning lamps and scanning mirror. As the cam rotates with the main driving shaft 187, a cam follower 330 moves the ball spline cam follower arm 331 within the stationary frame'332. The stationary frame 332 is fastened to the machine frame via flanges 333 and 334. Within the stationary frames are ball bushings 335 and 336 which allow the cam follower arm 331 to move back and forth through the stationary flange without rotation as the cam 327 rotates with the drive shaft 187. A return spring 337 attached between a dog 338 on the cam follower arm and to a spring anchor 339 fastened to the stationary frame 332 ensures that the cam follower 330 maintains intimate contact with the cam.

Welded or otherwise fastened onto the ball spline follower arm 331 is a driver arm 340. It is through this driver arm 340 that the mirror crank arm 341 and the lamp crank arm 342 transmit movement to the scanning mirror 21 and the lamps assembly for the lamps 33. The driver arm 340 has one pin 343 which fits into a slot 344 in the mirror crankarm 341 and a second pin 345 for cooperative action with a slot 346 in the lamp crank arm 342. The mirror crank arm 341 is fastened to the mirror shaft 313 by a slip hub 347 tightly clamped around the shaft 313. The lamp crank arm 342 is fastened to a hollow lamp drive shaft 348 by a split hub 349 tightly clamped to the lamp drive shaft. The lamp crank arm and hub clear the mirror shaft 313 without contacting it.

As the cam follower arm 331 moves through the bushings 335 and 336 it carries with it the driver arm 340. The mirror crank arm 341 and lamp'crank arm 342 are slaved to the driver arm 340 because they are slotted around the driving pins 343 and 345. This causes them to move at their slotted end according to the movement of the cam follower arm 331. This movement in turn causes the rotation of the mirror shaft 313 and hollow lamp drive shaft 348. When the mirror shaft 313 rotates it moves a shaft coupling 350 which moves the oscillating mirror frame 351a attached to the shaft extension 313a of shaft 313 by sleeve bearings 353 and 353. The mirror frame 351 holds the support to the mirror 21 through clamps 354 and mirror side supports 355 and 356.

The lamp crank arm 342 moving with the driver arm 340 drives the lamps across the platen. The lamp drive shaft moves the lamps through a flange 357 which mounts to the lamp frame 17. The side frame 314 holding the lamps is mounted through a sleeve bearing 358 to the main frame of the machine 316. The main frame also extends across the lamp shaft supporting it by main frame extensions 359 and 360 through bearings 361 and 362 respectively.

The driving system utilizes the cam profile and follower arm motion to drive the scanning mirror 21 at a uniform annular velocity. The system allows the object to be represented as a scanning font on the surface of the injecting electrode drum such that the font has the same tangential velocity as the injecting electrode surface at the imaging position near the aperture slot 146.

DRIVE MECHANISM The major components of the preferred embodiment of this machine are driven in a timed synchronous movement. The components driven from the main drive system include the imaging electrodes at station B, the optical system of station C, the transfer roller mechanism at station D and the injecting electrode cylinder housing.

The main power source is the drive motor 700 which drives the motor shaft 701 thereby rotating the driving sprocket 702 with a drive chain 703 wrapped therearound. The chain 703 connects to the sprocket 704 which drives the worm housed within the gear box 184. (The internal workings of the gear box are shown in FIG. 5.) The worm drives a sprocket which is mated with the machine drive shaft 187 for turning the injecting electrode cylinder housing.

Also mated to the shaft 187 is the optical driving cam 327. The rotation of the shaft 187 rotates the cam 327 causing the cam follower arm 331 to reciprocate within the stationary frame 332. Fastened securely to the follower arm 331 is the driver arm 340 pinned to develop the timed movement of the lamps 33 and the scan mirror 21 with the injecting electrode 1.

This movement is accomplished by connecting slots within mirror crank arm 341 and the lamp crank arm 342 to pins in the driver arm 340. The pin locations and arm lengths are related in such a manner that when the follower arm 331 moves through the fixed frame 332 the lamps and mirror traverse the platen 19 timed relative to each other and to the injecting electrode 1. The timing enables optical projection of a flowing illuminated image of the object at the platen 19 through the slit 146 at the imaging zone between the injecting electrode and the imaging electrode contacting it. The mirror crank arm 341 rotates the mirror shaft 313 while the lamp crank arm 342 rotates the lamp shaft 348.

While this motion occurs, a main component drive sprocket 705, which like the optical cam 327 is fitted or keyed for no-slip'movement with the shaft 187, rotates the main component drive chain 706. The chain 706 connects to the sprocket 707 operating through a common shaft 708 and gearing 709 to drive a chain 710 for bringing power to the sprocket drive 443 of the transfer roller 40. This portion of the drive system causes the rotation of the transfer roll 40 at the same surface velocity as the injecting electrode 1 so that the image on the injecting electrode may be transferred by contact through the final image support material at the transfer roll. The movement between the surface of the transfer roll and the injecting electrode must be a rolling, no-slip contact so that the image is not smeared when transferred from the injecting electrode to the support material sheet.

Another important function of the main drive system is to drive the imaging electrodes 16 and 29 at the proper surface velocity when they are contacting the injecting electrode 1. Therefore, the main imaging module drive sprocket 711 is driven by the chain 706 for transmitting power to the chain 530 driving the sprockets 531 and 532 connected to the first and second imaging rollers respectively.

The imaging electrodes are turned from power transmitted by the main imaging electrode drive sprocket 711 to the driven sprocket 712. They are both commonly shafted along a shaft 713. the chain 530 is maintained around the sprocket 712 and an idler 714 mounted onto the frame of the machine.

It is beneficial to the operation of the machine to continue the rotation of the imaging electrode rollers 16 and 29 for cleaning after the completion of the imaging cycle. Therefore, the secondary motor 715 drives a chain 716 to a sprocket 717 commonly shafted along shaft 713 with the main driver sprocket 711 and the driven sprocket 712 of the imaging electrode roller module. The motor 715 is started when the electrical clutch coupling 718 is de-energized adter the imaging cycle. The motor runs during the warmup and image cycle shutdown of the machine until the machine is turned off, thus rotating the two electrode rollers in order to clean the surfaces of residual suspension to prevent pigment interference with later images to be formed. The sprocket 717 rides on the shaft 713 separated by a mechanical overrunning clutch 720 in the sprocket 717. This clutch permits movement of the shaft 711 without turning the sprocket 717. However, when the main drive motor 700 is disengaged, the secondary drive motor 716 is engaged to turn the sprocket 717. The overriding clutch 720 moves the shaft 713 which causes the driven sprocket 712 and chain 530 running thereover to move the two imaging electrode rollers. When this occurs, the electrical clutch coupling 718 prevents the movement of the shaft 713 from affecting the chain 706 and the main drive system.

The cleaning module is not affected by nor connected with the main drive system of the machine. It is separately powered by motors attached to the cleaning module to independently turn the cleaning members 6, 7 and 8. There is no requirement that the cleaning module be tied directly into the main drive system since there is no need for simultaneous or imagewise precise movement between the cleaning members and the injecting electrode 1.

While this invention has been described with reference to the structures disclosed herein and while certain theories have been expressed to explain the experimentally obtainable results obtained, it is not confined to the details set forth; and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

What is claimed is:

1. An article capable of use in an optical system including:

l. a housing being generally cylindrical in shape and having (a) a first circumferential area being formed as a first aperture in said housing, (b) transparent material mounted in said first aperture, (c) and a second circumferential area being formed as a second aperture in said housing, said second aperture being at least as large as said first aperture, said first aperture and said second aperture being located on generally opposite portions of the circumference of said housing so that optical light rays may pass through said housing from said second aperture to said first aperture,

2. means to mount said housing for movement in a rotational path,

3. means to couple said housing to a power source for rotating said housing at a constant speed,

4. light shield means mounted within the volume enclosed by said housing, said light shield means including brackets mounted on the sides thereof and 5. lamp sockets mounted on said brackets.

2. An article capable of use in an optical system including:

l. a housing being generally cylindrical in shape and having (a) a first circumferential area being formed as a first aperture in said housing, (b) transparent material mounted in said first aperture, (c) and a second circumferential area being formed as a second aperture in said housing, said second aperture being at least as large as said first aperture, said first aperture and said second aperture being located on generally opposite portions of the circumference of said housing so that optical light rays may pass through said housing from said second aperture to said first aperture,

2. means to mount said housing for movement in a rotational path,

3. means to couple said housing to a power source for rotating said housing at a constant speed,

4. a stationary light shield mounted within the volume enclosed by said housing,

5. bearing means between said light shield and said housing and 6. means mounting said light shield within said housing for preventing movement of said light shield during rotation of said housing.

3. An article capable of use in an optical system including:

l. a housing being generally cylindrical in shape and having (a) a first circumferential area being formed as a first aperture in said housing, (b) transparent electrically conductive material mounted in said first aperture, (c) and a second circumferential arda being formed as a second aperture in said housing, said second aperture being at least as large as said first aperture, said first aperture and said second aperture being located on generally opposite portions of the circumference of said housing so that optical light rays may pass through said housing from said second aperture to said first aperture,

means to mount said housing for movement in a rotational path and 3. means to couple said housing to a power source for rotating said housing at a constant speed. 4. Optical means including:

1. optical scanning means capable of projecting light rays along an optical path from an object plane to an imaging zone,

2. housing means positioned along the optical path adjacent said imaging zone, said housing being of a continuous configuration and having a. a first peripheral area being formed as a first aperture in said housing means,

b. transparent, electrically conductive material mounted in said first aperture,

c. a second peripheral area being formed as a second aperture in said housing means,

. means to movably mount said housing means in the optical path whereby the light rays may pass from the second aperture to the first aperture and imaging zone, and

. means to drive said optical scanning means and said housing means in synchronism whereby the transparent, electrically conductive material passes through the imaging zone while the optical scanning means is projecting light rays from the object plane through the second aperture to the imaging zone.

5. Optical apparatus including: 1. optical scanning means capable of projecting light rays along an optical path from an object plane to an imaging zone,

. first drive means to couple said optical scanning means to a power source,

. housing means positioned along the optical path means to mount said housing whereby the optical path extends through the second aperture and then the first aperture,

. second drive means to couple said housing to a power source for rotating said housing so that the peripheral areas thereof pass through said imaging zone and means to operate said first and second drive means in a predetermined synchronous cycle of operation. 

1. An article capable of use in an optical system including:
 1. a housing being generally cylindrical in shape and having (a) a first circumferential area being formed as a first aperture in said housing, (b) transparent material mounted in said first aperture, (c) and a second circumferential area being formed as a second aperture in said housing, said second aperture being at least as large as said first aperture, said first aperture and said second aperture being located on generally opposite portions of the circumference of said housing so that optical light rays may pass through said housing from said second aperture to said first aperture,
 2. means to mount said housing for movement in a rotational path,
 3. means to couple said housing to a power source for rotating said housing at a constant speed,
 4. light shield means mounted within the volume enclosed by said housing, said light shield means including brackets mounted on the sides thereof and
 5. lamp sockets mounted on said brackets.
 2. means to mount said housing for movement in a rotational path and
 2. means to mount said housing for movement in a rotational path,
 2. An article capable of use in an optical system including:
 2. means to mount said housing for movement in a rotational path,
 2. first drive means to couple said optical scanning means to a power source,
 2. housing means positioned along the optical path adjacent said imaging zone, said housing being of a continuous configuration and having a. a first peripheral area being formed as a first aperture in said housing means, b. transparent, electrically conductive material mounted in said first aperture, c. a second peripheral area being formed as a second aperture in said housing means,
 3. means to movably mount said housing means in the optical path whereby the light rays may pass from the second aperture to the first aperture and imaging zone, and
 3. means to couple said housing to a power source for rotating said housing at a constant speed.
 3. housing means positioned along the optical path adjacent said imaging zone, said housing being of a cylindrical configuration and having a. a first peripheral area being formed as a first aperture in said housing, b. transparent material mounted in said first aperture, c. a second peripheral area being formed as a second aperture in said housing,
 3. An article capable of use iN an optical system including:
 3. means to couple said housing to a power source for rotating said housing at a constant speed,
 3. means to couple said housing to a power source for rotating said housing at a constant speed,
 4. light shield means mounted within the volume enclosed by said housing, said light shield means including brackets mounted on the sides thereof and
 4. a stationary light shield mounted within the volume enclosed by said housing,
 4. means to mount said housing whereby the optical path extends through the second aperture and then the first aperture,
 4. means to drive said optical scanning means and said housing means in synchronism whereby the transparent, electrically conductive material passes through the imaging zone while the optical scanning means is projecting light rays from the object plane through the second aperture to the imaging zone.
 4. Optical means including:
 5. Optical apparatus including:
 5. second drive means to couple said housing to a power source for rotating said housing so that the peripheral areas thereof pass through said imaging zone and
 5. bearing means between said light shield and said housing and
 5. lamp sockets mounted on said brackets.
 6. means mounting said light shield within said housing for preventing movement of said light shield during rotation of said housing.
 6. means to operate said first and second drive means in a predetermined synchronous cycle of operation. 